Mortality Up With 80 Percent Oxygen in Abdominal Surgery

TUESDAY, Oct. 2 (HealthDay News) -- For patients undergoing abdominal surgery, use of 80 percent oxygen in the perioperative period is associated with an increased risk of long-term mortality, which is statistically significant for cancer patients but not for non-cancer patients, according to a study published in the October issue of Anesthesia & Analgesia.

Christian S. Meyhoff, M.D., Ph.D., from Copenhagen University Hospital in Denmark, and colleagues examined the correlation between long-term mortality and perioperative oxygen fraction in patients undergoing abdominal surgery. A total of 1,386 patients undergoing elective or emergency laparotomy from October 2006 to October 2008 were randomly allocated to receive 30 or 80 percent oxygen during, and for two hours following surgery. Patients were followed through February 2010 and vital status was recorded for 1,382 patients.

After a median follow-up of 2.3 years, the researchers found that, 23.2 percent of patients died in the 80 percent oxygen group (159 of 685 patients), compared with 18.3 percent (128 of 701 patients) in the 30 percent oxygen group, for a hazard ratio of 1.30 (P = 0.03). For patients undergoing cancer surgery, the hazard ratio was significant (1.45; P = 0.009), while the hazard ratio was not significant (1.06; P = 0.79) for those undergoing non-cancer surgery.

"We conclude that administration of 80 percent oxygen during, and for two hours after abdominal surgery, compared to 30 percent oxygen, is associated with a significantly increased long-term all-cause mortality that appears to be statistically significant in patients undergoing cancer surgery but not in non-cancer patients," the authors write.